Labour MP Seema Malhotra, who has organised the letter to the prime minister.
Photograph: Lauren Hurley/PA

More than 60 MPs have written to Theresa May asking that the government immediately ratify the Istanbul convention, an international agreement aimed at ending violence against women.

The letter, organised by the Labour MP Seema Malhotra, comes as her fellow MPs on Thursday debate a Commons motion to mark the International Day for the Elimination of Violence against Women and Girls.

The letter to May notes that when she was home secretary she promised to tackle domestic violence and establish a cross-departmental strategy on tackling violence against women and girls, and that her government spoke out about such matters.

“But, as we are sure you will agree, words are not enough,” it continues, adding that violence against women perpetrated by a partner or acquaintance increased rapidly between 2009 and 2014, as did reports of child sexual abuse and domestic violence.

“Funding for staff who provide individual and tailored support for victims of violence to rebuild their lives and seek prosecution of their abusers is being cut,” the 65 MPs say. “We believe that by their actions (and failures to act), your ministers are failing to deliver on your commitment to tackling sexual abuse and violence. We are therefore asking you to take leadership on these issues immediately.”

The letter says that of “particular importance” is the failure to ratify the Istanbul convention. The UK signed up to the measure in 2012, but has not yet ratified it.

The convention, which originates from the Council of Europe, says it is “the obligation of the state” to tackle violence against women. Previously, the government has explained the delay by saying it was looking into how the convention might affect jurisdictions.

“This historic international treaty sets legally binding standards for preventing and tackling domestic abuse,” the MPs’ letter says. “Crucially, the convention prevents further cuts to domestic violence refuges and gives all survivors of domestic abuse the right to access the specialist services which they need to live in safety and rebuild their lives.”

It concludes: “Your ministers have uttered warm words about their commitment to passing the Istanbul convention, but until we see government time set aside in the parliamentary calendar, it remains nothing more than a piece of paper, and the UK will be failing in its obligations to tackle and eliminate violence against women and girls.”

In a parallel move on Thursday, the Scottish National party MP Eilidh Whiteford launched a private member’s bill calling on the government to ratify the convention.

Whiteford said: “We’ve been waiting over four and a half years for the UK government to ratify the Istanbul convention. It is no longer a valid excuse to say there is not enough parliamentary time to take forward the necessary changes to domestic legislation.”

Her bill is intended to set out a clear timetable to bring forward the required legislation.

Last week, the Scottish government’s communities secretary, Angela Constance, called on the UK government to act over the convention, writing to the home secretary, Amber Rudd, asking for a “clear timetable” for ratification.